Social media has dramatically changed the Internet landscape. Users gather information and actively disseminate it, influencing information spread and credibility. Consequently, many Americans are much more engaged in public discourse on social media than when older media such as television dominated the media terrain. Our team proposes to evaluate the effectiveness of employing social media in a public health communication campaign directed to mothers of adolescent daughters with the goal of decreasing indoor tanning (IT) by adolescent girls. This research is significant because many health agencies and organizations rely on social media yet there is a paucity of research on their potential influence in health communication campaigns. This research gap has led to calls for investigations that identify best practices for social media in such campaigns, including by NIH, and our proposed research will fill this gap. The focus on preventing IT by minors is also significant because IT has been linked to elevated risk for developing melanoma. Many states have enacted bans on access to IT by minors, but many laws include exceptions for parental permission. Current parental-permission laws are less effective at reducing IT by teen girls than age restrictions. The social media campaign seeks to reduce mothers' IT permissiveness to maximize the effectiveness of parental- permission laws. The specific aims are to: 1) develop and implement a social media campaign for mothers on health and wellness of adolescent daughters that includes theory-based messaging advocating adolescent girls avoid IT and 2) evaluate the effectiveness of the IT messages at a) decreasing mothers' permissiveness for daughters to indoor tan and daughters' perceptions of their permissiveness, b) reducing the prevalence of IT by mothers and daughters, and c) increasing the number of mothers who support strengthening bans on IT by minors. Mother/daughter pairs from secondary schools in Eastern Tennessee, recruited with the help of the state's Coordinated School Health program, will be enrolled in a group-randomized controlled design; Tennessee requires parental permission for minors to indoor tan. The IT messages will be delivered to mothers through an integrated social media campaign using Facebook, Twitter, YouTube, Pinterest, and Instagram over two school years (18 months). Schools will be assigned by county to receive a health and wellness social media campaign with (intervention) or without (control) IT messages. Mothers and daughters will be assessed at baseline and 6- and 12-months after the campaign concludes, with validated self-report measures of mothers' permissiveness for daughter to indoor tan and mothers' and daughters' prevalence of IT. Mothers' support for a complete ban on IT by minors will be objectively assessed by asking them to take actions to advocate for a ban to their state legislators (i.e., sign a petition, send a letter/meeting request, volunteer to attend a hearing). Secondary aims are to analyze potential moderators (e.g., mother/daughter characteristics; mothers' political ideology) and mediation of campaign effectiveness by theoretical concepts and campaign engagement.